Tumour bed biopsy detects the presence of multifocal disease in patients undergoing breast conservation therapy for primary breast carcinoma.

This study prospectively examined tumour bed biopsies in 135 consecutive patients undergoing conservative surgery for breast carcinoma. All had wide resection of the primary tumour and histologically clear margins. Twelve patients (9%) had positive tumour bed biopsies. Two subgroups of patients had positive bed biopsies; those with ductal carcinoma in situ, and a second group with more aggressive disease characterized by lymph node involvement, vascular invasion and a higher grade and mitotic count. As the majority of recurrences from breast carcinoma occur in the region of the primary tumour, bed biopsy may aid in the identification of a group of patients with multifocal or aggressive disease who are at increased risk of local recurrence.